What is the genotype for classic sickle cell disease?

What is the genotype for classic sickle cell disease?

• A. HgbAS
• B. HgbSS
• C. HgbSS Trait
• D. HgbSA

Answer: (B)

Sickle cell disease occurs when a person inherits two copies of the sickle cell allele. This means they are homozygous for HbS, written as HbS/HbS (often abbreviated HbSS). When one HbS allele pairs with a normal HbA allele (HbA/HbS), the person has sickle cell trait, not the disease. The two HbS alleles cause hemoglobin to polymerize when deoxygenated, leading to sickling of red blood cells, hemolytic anemia, and complications like vaso-occlusive crises. Therefore, the genotype for classic sickle cell disease is HbS/HbS.

Sickle cell disease occurs when a person inherits two copies of the sickle cell allele. This means they are homozygous for HbS, written as HbS/HbS (often abbreviated HbSS). When one HbS allele pairs with a normal HbA allele (HbA/HbS), the person has sickle cell trait, not the disease. The two HbS alleles cause hemoglobin to polymerize when deoxygenated, leading to sickling of red blood cells, hemolytic anemia, and complications like vaso-occlusive crises. Therefore, the genotype for classic sickle cell disease is HbS/HbS.